1. One of Wikipedia's first rules regarding sources is "No Original Research." The idea is that Wikipedia editors should be at least a bit removed from what they're writing about. Lockley basically sidestepped this rule when he started editing the article as early as 2012, published his book, and then kept making changes based on his published work.

2. Peer-reviewed scholarly articles are considered prime material for sources on Wikipedia. Completely removing them would be strange at the best of times. Removing them in favor of less specialized texts is even odder.

3. By editing Wikipedia to become its main source, Lockley basically created a reputation as the "only" major scholar in the field by process of elimination.

4. He actually cited one of his own papers before it was even published. Doing this in general is often suspect on Wikipedia because, again, "no original research."

It doesn't prove that Lockley is actively lying about Yasuke, but it does mean that he's self-serving at the expense of his academic integrity. And without integrity, why would we believe anything he says?